/*-
 *   BSD LICENSE
 *
 *   Copyright (c) Intel Corporation.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "spdk/env.h"
#include "spdk/log.h"
#include "spdk/nvme.h"
#include "spdk/nvme_zns.h"
#include "spdk/stdinc.h"
#include "spdk/string.h"
#include "spdk/vmd.h"

struct ctrlr_entry {
  struct spdk_nvme_ctrlr *ctrlr;
  TAILQ_ENTRY(ctrlr_entry) link;
  char name[1024];
};

struct ns_entry {
  struct spdk_nvme_ctrlr *ctrlr;
  struct spdk_nvme_ns *ns;
  TAILQ_ENTRY(ns_entry) link;
  struct spdk_nvme_qpair *qpair;
};

static TAILQ_HEAD(, ctrlr_entry)
    g_controllers = TAILQ_HEAD_INITIALIZER(g_controllers);
static TAILQ_HEAD(,
                  ns_entry) g_namespaces = TAILQ_HEAD_INITIALIZER(g_namespaces);
static struct spdk_nvme_transport_id g_trid = {};

static bool g_vmd = false;

static void register_ns(struct spdk_nvme_ctrlr *ctrlr,
                        struct spdk_nvme_ns *ns) {
  struct ns_entry *entry;

  if (!spdk_nvme_ns_is_active(ns)) {
    return;
  }

  entry = (ns_entry *)malloc(sizeof(struct ns_entry));
  if (entry == NULL) {
    perror("ns_entry malloc");
    exit(1);
  }

  entry->ctrlr = ctrlr;
  entry->ns = ns;
  TAILQ_INSERT_TAIL(&g_namespaces, entry, link);

  printf("  Namespace ID: %d size: %juGB\n", spdk_nvme_ns_get_id(ns),
         spdk_nvme_ns_get_size(ns) / 1000000000);
}

struct hello_world_sequence {
  struct ns_entry *ns_entry;
  char *buf;
  unsigned using_cmb_io;
  int is_completed;
};

static void read_complete(void *arg, const struct spdk_nvme_cpl *completion) {
  struct hello_world_sequence *sequence = (hello_world_sequence *)arg;

  /* Assume the I/O was successful */
  sequence->is_completed = 1;
  /* See if an error occurred. If so, display information
   * about it, and set completion value so that I/O
   * caller is aware that an error occurred.
   */
  if (spdk_nvme_cpl_is_error(completion)) {
    spdk_nvme_qpair_print_completion(sequence->ns_entry->qpair,
                                     (struct spdk_nvme_cpl *)completion);
    fprintf(stderr, "I/O error status: %s\n",
            spdk_nvme_cpl_get_status_string(&completion->status));
    fprintf(stderr, "Read I/O failed, aborting run\n");
    sequence->is_completed = 2;
    exit(1);
  }

  /*
   * The read I/O has completed.  Print the contents of the
   *  buffer, free the buffer, then mark the sequence as
   *  completed.  This will trigger the hello_world() function
   *  to exit its polling loop.
   */
  printf("%s", sequence->buf);
  spdk_free(sequence->buf);
}

static void write_complete(void *arg, const struct spdk_nvme_cpl *completion) {
  struct hello_world_sequence *sequence = (hello_world_sequence *)arg;
  struct ns_entry *ns_entry = sequence->ns_entry;
  int rc;

  /* See if an error occurred. If so, display information
   * about it, and set completion value so that I/O
   * caller is aware that an error occurred.
   */
  if (spdk_nvme_cpl_is_error(completion)) {
    spdk_nvme_qpair_print_completion(sequence->ns_entry->qpair,
                                     (struct spdk_nvme_cpl *)completion);
    fprintf(stderr, "I/O error status: %s\n",
            spdk_nvme_cpl_get_status_string(&completion->status));
    fprintf(stderr, "Write I/O failed, aborting run\n");
    sequence->is_completed = 2;
    exit(1);
  }
  /*
   * The write I/O has completed.  Free the buffer associated with
   *  the write I/O and allocate a new zeroed buffer for reading
   *  the data back from the NVMe namespace.
   */
  if (sequence->using_cmb_io) {
    spdk_nvme_ctrlr_unmap_cmb(ns_entry->ctrlr);
  } else {
    spdk_free(sequence->buf);
  }
  sequence->buf = (char *)spdk_zmalloc(0x1000, 0x1000, NULL,
                                       SPDK_ENV_SOCKET_ID_ANY, SPDK_MALLOC_DMA);

  rc = spdk_nvme_ns_cmd_read(ns_entry->ns, ns_entry->qpair, sequence->buf,
                             0, /* LBA start */
                             1, /* number of LBAs */
                             read_complete, (void *)sequence, 0);
  if (rc != 0) {
    fprintf(stderr, "starting read I/O failed\n");
    exit(1);
  }
}

static void reset_zone_complete(void *arg,
                                const struct spdk_nvme_cpl *completion) {
  struct hello_world_sequence *sequence = (hello_world_sequence *)arg;

  /* Assume the I/O was successful */
  sequence->is_completed = 1;
  /* See if an error occurred. If so, display information
   * about it, and set completion value so that I/O
   * caller is aware that an error occurred.
   */
  if (spdk_nvme_cpl_is_error(completion)) {
    spdk_nvme_qpair_print_completion(sequence->ns_entry->qpair,
                                     (struct spdk_nvme_cpl *)completion);
    fprintf(stderr, "I/O error status: %s\n",
            spdk_nvme_cpl_get_status_string(&completion->status));
    fprintf(stderr, "Reset zone I/O failed, aborting run\n");
    sequence->is_completed = 2;
    exit(1);
  }
}

static void
reset_zone_and_wait_for_completion(struct hello_world_sequence *sequence) {
  if (spdk_nvme_zns_reset_zone(sequence->ns_entry->ns,
                               sequence->ns_entry->qpair,
                               0,     /* starting LBA of the zone to reset */
                               false, /* don't reset all zones */
                               reset_zone_complete, sequence)) {
    fprintf(stderr, "starting reset zone I/O failed\n");
    exit(1);
  }
  while (!sequence->is_completed) {
    spdk_nvme_qpair_process_completions(sequence->ns_entry->qpair, 0);
  }
  sequence->is_completed = 0;
}

static void hello_world(void) {
  struct ns_entry *ns_entry;
  struct hello_world_sequence sequence;
  int rc;
  size_t sz;

  TAILQ_FOREACH(ns_entry, &g_namespaces, link) {
    /*
     * Allocate an I/O qpair that we can use to submit read/write requests
     *  to namespaces on the controller.  NVMe controllers typically support
     *  many qpairs per controller.  Any I/O qpair allocated for a controller
     *  can submit I/O to any namespace on that controller.
     *
     * The SPDK NVMe driver provides no synchronization for qpair accesses -
     *  the application must ensure only a single thread submits I/O to a
     *  qpair, and that same thread must also check for completions on that
     *  qpair.  This enables extremely efficient I/O processing by making all
     *  I/O operations completely lockless.
     */
    ns_entry->qpair = spdk_nvme_ctrlr_alloc_io_qpair(ns_entry->ctrlr, NULL, 0);
    if (ns_entry->qpair == NULL) {
      printf("ERROR: spdk_nvme_ctrlr_alloc_io_qpair() failed\n");
      return;
    }

    /*
     * Use spdk_dma_zmalloc to allocate a 4KB zeroed buffer.  This memory
     * will be pinned, which is required for data buffers used for SPDK NVMe
     * I/O operations.
     */
    sequence.using_cmb_io = 1;
    sequence.buf = (char *)spdk_nvme_ctrlr_map_cmb(ns_entry->ctrlr, &sz);
    if (sequence.buf == NULL || sz < 0x1000) {
      sequence.using_cmb_io = 0;
      sequence.buf = (char *)spdk_zmalloc(
          0x1000, 0x1000, NULL, SPDK_ENV_SOCKET_ID_ANY, SPDK_MALLOC_DMA);
    }
    if (sequence.buf == NULL) {
      printf("ERROR: write buffer allocation failed\n");
      return;
    }
    if (sequence.using_cmb_io) {
      printf("INFO: using controller memory buffer for IO\n");
    } else {
      printf("INFO: using host memory buffer for IO\n");
    }
    sequence.is_completed = 0;
    sequence.ns_entry = ns_entry;

    /*
     * If the namespace is a Zoned Namespace, rather than a regular
     * NVM namespace, we need to reset the first zone, before we
     * write to it. This not needed for regular NVM namespaces.
     */
    if (spdk_nvme_ns_get_csi(ns_entry->ns) == SPDK_NVME_CSI_ZNS) {
      reset_zone_and_wait_for_completion(&sequence);
    }

    /*
     * Print "Hello world!" to sequence.buf.  We will write this data to LBA
     *  0 on the namespace, and then later read it back into a separate buffer
     *  to demonstrate the full I/O path.
     */
    snprintf(sequence.buf, 0x1000, "%s", "Hello world!\n");

    /*
     * Write the data buffer to LBA 0 of this namespace.  "write_complete" and
     *  "&sequence" are specified as the completion callback function and
     *  argument respectively.  write_complete() will be called with the
     *  value of &sequence as a parameter when the write I/O is completed.
     *  This allows users to potentially specify different completion
     *  callback routines for each I/O, as well as pass a unique handle
     *  as an argument so the application knows which I/O has completed.
     *
     * Note that the SPDK NVMe driver will only check for completions
     *  when the application calls spdk_nvme_qpair_process_completions().
     *  It is the responsibility of the application to trigger the polling
     *  process.
     */
    rc = spdk_nvme_ns_cmd_write(ns_entry->ns, ns_entry->qpair, sequence.buf,
                                0, /* LBA start */
                                1, /* number of LBAs */
                                write_complete, &sequence, 0);
    if (rc != 0) {
      fprintf(stderr, "starting write I/O failed\n");
      exit(1);
    }

    /*
     * Poll for completions.  0 here means process all available completions.
     *  In certain usage models, the caller may specify a positive integer
     *  instead of 0 to signify the maximum number of completions it should
     *  process.  This function will never block - if there are no
     *  completions pending on the specified qpair, it will return immediately.
     *
     * When the write I/O completes, write_complete() will submit a new I/O
     *  to read LBA 0 into a separate buffer, specifying read_complete() as its
     *  completion routine.  When the read I/O completes, read_complete() will
     *  print the buffer contents and set sequence.is_completed = 1.  That will
     *  break this loop and then exit the program.
     */
    while (!sequence.is_completed) {
      spdk_nvme_qpair_process_completions(ns_entry->qpair, 0);
    }

    /*
     * Free the I/O qpair.  This typically is done when an application exits.
     *  But SPDK does support freeing and then reallocating qpairs during
     *  operation.  It is the responsibility of the caller to ensure all
     *  pending I/O are completed before trying to free the qpair.
     */
    spdk_nvme_ctrlr_free_io_qpair(ns_entry->qpair);
  }
}

static bool probe_cb(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
                     struct spdk_nvme_ctrlr_opts *opts) {
  printf("Attaching to %s\n", trid->traddr);

  return true;
}

static void attach_cb(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
                      struct spdk_nvme_ctrlr *ctrlr,
                      const struct spdk_nvme_ctrlr_opts *opts) {
  int nsid;
  struct ctrlr_entry *entry;
  struct spdk_nvme_ns *ns;
  const struct spdk_nvme_ctrlr_data *cdata;

  entry = (ctrlr_entry *)malloc(sizeof(struct ctrlr_entry));
  if (entry == NULL) {
    perror("ctrlr_entry malloc");
    exit(1);
  }

  printf("Attached to %s\n", trid->traddr);

  /*
   * spdk_nvme_ctrlr is the logical abstraction in SPDK for an NVMe
   *  controller.  During initialization, the IDENTIFY data for the
   *  controller is read using an NVMe admin command, and that data
   *  can be retrieved using spdk_nvme_ctrlr_get_data() to get
   *  detailed information on the controller.  Refer to the NVMe
   *  specification for more details on IDENTIFY for NVMe controllers.
   */
  cdata = spdk_nvme_ctrlr_get_data(ctrlr);

  snprintf(entry->name, sizeof(entry->name), "%-20.20s (%-20.20s)", cdata->mn,
           cdata->sn);

  entry->ctrlr = ctrlr;
  TAILQ_INSERT_TAIL(&g_controllers, entry, link);

  /*
   * Each controller has one or more namespaces.  An NVMe namespace is basically
   *  equivalent to a SCSI LUN.  The controller's IDENTIFY data tells us how
   *  many namespaces exist on the controller.  For Intel(R) P3X00 controllers,
   *  it will just be one namespace.
   *
   * Note that in NVMe, namespace IDs start at 1, not 0.
   */
  for (nsid = spdk_nvme_ctrlr_get_first_active_ns(ctrlr); nsid != 0;
       nsid = spdk_nvme_ctrlr_get_next_active_ns(ctrlr, nsid)) {
    ns = spdk_nvme_ctrlr_get_ns(ctrlr, nsid);
    if (ns == NULL) {
      continue;
    }
    register_ns(ctrlr, ns);
  }
}

static void cleanup(void) {
  struct ns_entry *ns_entry, *tmp_ns_entry;
  struct ctrlr_entry *ctrlr_entry, *tmp_ctrlr_entry;
  struct spdk_nvme_detach_ctx *detach_ctx = NULL;

  TAILQ_FOREACH_SAFE(ns_entry, &g_namespaces, link, tmp_ns_entry) {
    TAILQ_REMOVE(&g_namespaces, ns_entry, link);
    free(ns_entry);
  }

  TAILQ_FOREACH_SAFE(ctrlr_entry, &g_controllers, link, tmp_ctrlr_entry) {
    TAILQ_REMOVE(&g_controllers, ctrlr_entry, link);
    spdk_nvme_detach_async(ctrlr_entry->ctrlr, &detach_ctx);
    free(ctrlr_entry);
  }

  if (detach_ctx) {
    spdk_nvme_detach_poll(detach_ctx);
  }
}

static void usage(const char *program_name) {
  printf("%s [options]", program_name);
  printf("\t\n");
  printf("options:\n");
  printf("\t[-d DPDK huge memory size in MB]\n");
  printf("\t[-g use single file descriptor for DPDK memory segments]\n");
  printf("\t[-i shared memory group ID]\n");
  printf("\t[-r remote NVMe over Fabrics target address]\n");
  printf("\t[-V enumerate VMD]\n");
#ifdef DEBUG
  printf("\t[-L enable debug logging]\n");
#else
  printf("\t[-L enable debug logging (flag disabled, must reconfigure with "
         "--enable-debug)\n");
#endif
}

static int parse_args(int argc, char **argv, struct spdk_env_opts *env_opts) {
  int op, rc;

  spdk_nvme_trid_populate_transport(&g_trid, SPDK_NVME_TRANSPORT_PCIE);
  snprintf(g_trid.subnqn, sizeof(g_trid.subnqn), "%s", SPDK_NVMF_DISCOVERY_NQN);

  while ((op = getopt(argc, argv, "d:gi:r:L:V")) != -1) {
    switch (op) {
    case 'V':
      g_vmd = true;
      break;
    case 'i':
      env_opts->shm_id = spdk_strtol(optarg, 10);
      if (env_opts->shm_id < 0) {
        fprintf(stderr, "Invalid shared memory ID\n");
        return env_opts->shm_id;
      }
      break;
    case 'g':
      env_opts->hugepage_single_segments = true;
      break;
    case 'r':
      if (spdk_nvme_transport_id_parse(&g_trid, optarg) != 0) {
        fprintf(stderr, "Error parsing transport address\n");
        return 1;
      }
      break;
    case 'd':
      env_opts->mem_size = spdk_strtol(optarg, 10);
      if (env_opts->mem_size < 0) {
        fprintf(stderr, "Invalid DPDK memory size\n");
        return env_opts->mem_size;
      }
      break;
    case 'L':
      rc = spdk_log_set_flag(optarg);
      if (rc < 0) {
        fprintf(stderr, "unknown flag\n");
        usage(argv[0]);
        exit(EXIT_FAILURE);
      }
#ifdef DEBUG
      spdk_log_set_print_level(SPDK_LOG_DEBUG);
#endif
      break;
    default:
      usage(argv[0]);
      return 1;
    }
  }

  return 0;
}

int main(int argc, char **argv) {
  int rc;
  struct spdk_env_opts opts;

  /*
   * SPDK relies on an abstraction around the local environment
   * named env that handles memory allocation and PCI device operations.
   * This library must be initialized first.
   *
   */
  spdk_env_opts_init(&opts);
  rc = parse_args(argc, argv, &opts);
  if (rc != 0) {
    return rc;
  }

  opts.name = "hello_world";
  if (spdk_env_init(&opts) < 0) {
    fprintf(stderr, "Unable to initialize SPDK env\n");
    return 1;
  }

  printf("Initializing NVMe Controllers\n");

  if (g_vmd && spdk_vmd_init()) {
    fprintf(stderr, "Failed to initialize VMD."
                    " Some NVMe devices can be unavailable.\n");
  }

  /*
   * Start the SPDK NVMe enumeration process.  probe_cb will be called
   *  for each NVMe controller found, giving our application a choice on
   *  whether to attach to each controller.  attach_cb will then be
   *  called for each controller after the SPDK NVMe driver has completed
   *  initializing the controller we chose to attach.
   */
  rc = spdk_nvme_probe(&g_trid, NULL, probe_cb, attach_cb, NULL);
  if (rc != 0) {
    fprintf(stderr, "spdk_nvme_probe() failed\n");
    rc = 1;
    goto exit;
  }

  if (TAILQ_EMPTY(&g_controllers)) {
    fprintf(stderr, "no NVMe controllers found\n");
    rc = 1;
    goto exit;
  }

  printf("Initialization complete.\n");
  hello_world();
  cleanup();
  if (g_vmd) {
    spdk_vmd_fini();
  }

exit:
  cleanup();
  spdk_env_fini();
  return rc;
}
